That's the average of all respondents. Take a look at the proportions of the Americans who are involved in religious activities, and how much time those who are involved spend on them.
Can secular leftists create political institutions on the Left that involve about 4.1% of the Americans every weekday, 15.2% of them every weekend, each of the participants spending 1.21 hours every weekday and 1.97 hours every weekend, and that get them to pay for the institutions' operational expenses, missions at home and abroad, and services to members and others? If we can, we can rival religious organizations -- if we can't, we can't.
<ftp://ftp.bls.gov/pub/news.release/atus.txt> Cf. Table 2. Average hours per day spent in primary activities (1) for the total population and for persons reporting the activity on the diary day by activity category and weekdays and weekends, 2005 annual averages -- Yoshie